|SUTIVISEDSAK, NONGNUCH - FORMER ARS EMPLOYEE|
Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2014
Publication Date: 3/1/2015
Publication URL: http://handle.nal.usda.gov/10113/60538
Citation: Leathers, T.D., Sutivisedsak, N., Nunnally, M.S., Price, N.P., Stanley, A.M. 2015. Enzymatic modification of schizophyllan. Biotechnology Letters. 37(3):673-678.
Interpretive Summary: In this research we developed a novel method for the modification of the valuable biopolymer, schizophyllan. Although schizophyllan is commercially produced for pharmaceutical and cosmetics uses, little information is available on controlled modifications of the polymer for novel applications. We used enzymes from novel fungal strains to progressively reduce the molecular weight and viscosity of schizophyllan. This information will enable researchers to develop new uses for schizophyllan.
Technical Abstract: An enzymatic method was developed for the progressive modification of the polysaccharide schizophyllan. Fungal strains Hypocrea nigricans NRRL 62555, Penicillium crustosum NRRL 62558, and Penicillium simplicissimum NRRL 62550 were previously identified as novel sources of ß-endoglucanase with specificity towards schizophyllan. Concentrated enzyme preparations from these strains showed specific activities of 1.7 to 4.3 U ß-glucanase/mg protein. Using dilutions of these enzymes in time course digestions, schizophyllan was progressively modified to reduced molecular weight species. Glucose and oligosaccharides were found only in the more complete digestions, and thus modified schizophyllan can be produced quantitatively, without loss to small molecules. Permethylation analysis confirmed that modified schizophyllan retains the fundamental linkage structure of native schizophyllan. Modified schizophyllan species showed progressively reduced viscosity profiles, and all exhibited pseudoplasticity in response to shear thinning.